Studies primarily emanating from the cognitive science literature suggest both advantages and disadvantages of bilingualism for cognitive performance. The Interference Hypothesis suggests that while interacting in two languages (e.g., English and Spanish), bilinguals'capacity to communicate in one language decreases as a function of the second language interfering in their language-based cognitive processes. The Inhibitory Control Model, a refinement of this hypothesis, states that bilinguals must suppress the non-target language to allow production of the intended language. This constant experience with linguistic conflict resolution can be seen as practice of executive and attentional control, thus predicting a bilingual advantage on tasks requiring these abilities. While most of the work in bilingual neuro-cognition has been conducted using such cognitive science paradigms, often with college students, translation Into competent healthcare for linguistically diverse groups requires understanding how these performance predictions fit into an applied neuropsychology work frame, such as would be used when delivering care, and with a broader demographic representation. Given that Spanish speakers in the U.S. vary in English fluency, it is important to understand how this second language fluency affects neuropsychological (NP) performance in the first language. This has implications for the interpretation of test results when diagnosing brain dysfunction in bilingual patients. To this end, the proposed study will examine the effects of English fluency on Spanish language neuropsychological test performance hypothesizing relationships derived from existing cognitive science models. In addition, it will explore whether bilingual advantages observed in our preliminary data are explained by socioeconomic and acculturation differences between bilinguals and monolinguals. Finally, in order to understand the clinical significance of these potential performance differences, the proposed study will examine whether clinically meaningful bilingual advantages are observed in HIV+ individuals, a patient population in whom brain dysfunction is common. Participants will be 80 healthy HIV- men and women (40 bilingual and 40 demographically comparable monolingual), and 40 bilingual and 40 monolingual HIV+ participants with comparable demographic and disease characteristics. All will be native Spanish speakers of Mexican descent. Bilingualism will be determined based on a language preference questionnaire as well as objective measures of verbal fluency in each language. Participants will receive neuropsychological and psychosocial assessments. The knowledge gained will help to bridge health disparities in the competent neuropsychological assessment of diverse populations. My most direct goal will be to carry out the research plan proposed in this application. PUBLIC HEALTH RELEVANCE: The goal of this type of research is to inform the development of valid ways to assess cognitive functioning in culturally and linguistically diverse populations. This will result in better quality of care across the spectrum of brain diseases, as such that caused by HIV. Understanding the ways in which socio-demographic characteristics impact cognition should ultimately, and ideally, not only affect the construction of assessment instruments but also point a direction in public policy toward maximizing the possibilities of an enriched developmental environment for people living under disadvantaged conditions. As a long-term goal Dr. Cherner and I would like to extend the already emerging international work of the HNRC by setting up collaborations with other Latin American countries, to study the impact of neuro AIDS and associated conditions such as toxoplasmosis in different regions. My hope is that we can disseminate the knowledge obtained here in the U.S. Dr. to various countries in Latin America. Dr. Cherner, being a native of Argentina, and I, being a native of Colombia, make this goal a plausible one. It is my long term goal as a scientist and professor of a University in the United States that to one day I will be able to disseminate culturally appropriate assessment tools in developing countries were the need is great but resources are limited.